body{
    counter-reset: row;
}
section{
    overflow: hidden;
    margin: 3px;
    font-size: 20px;
    line-height: 50px;
    text-align: center;
    color: #ff0909;
    background: #415481;
    counter-reset: box;
    counter-increment: row;
}
section:before{
    content: "row" counter(row) ":";
    float: left;
}
div{
    width: 50px;
    height: 50px;
    margin: 3px;
    background: aqua;
    float: left;
    counter-increment: box;
}
div:before{
    content: counter(row)"."counter(box);
}